You assume a value of t that is increased over the t in the equations.
(I don't have to do that, but you have to, so that you will understand the solution)
Let us the t in the equations is t=1.
x = -5*1 -3 = -8
Then, we increase t, say t = 3,
x = -5*3 -3 = -18
So, the x decreases as t increases. -------**